ed1a908e53
Prefix and bucket tables are initialized when entering established state but not explicitly freed when leaving it (that is handled by protocol restart). With graceful restart, BGP may enter and leave established state multiple times without hard protocol restart causing memory leak.
417 lines
17 KiB
C
417 lines
17 KiB
C
/*
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* BIRD -- The Border Gateway Protocol
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*
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* (c) 2000 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#ifndef _BIRD_BGP_H_
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#define _BIRD_BGP_H_
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#include <stdint.h>
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#include "nest/route.h"
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#include "nest/bfd.h"
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#include "lib/hash.h"
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struct linpool;
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struct eattr;
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struct bgp_config {
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struct proto_config c;
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u32 local_as, remote_as;
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ip_addr remote_ip;
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ip_addr source_addr; /* Source address to use */
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struct iface *iface; /* Interface for link-local addresses */
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u16 remote_port; /* Neighbor destination port */
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int multihop; /* Number of hops if multihop */
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int ttl_security; /* Enable TTL security [RFC5082] */
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int next_hop_self; /* Always set next hop to local IP address */
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int next_hop_keep; /* Do not touch next hop attribute */
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int missing_lladdr; /* What we will do when we don' know link-local addr, see MLL_* */
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int gw_mode; /* How we compute route gateway from next_hop attr, see GW_* */
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int compare_path_lengths; /* Use path lengths when selecting best route */
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int med_metric; /* Compare MULTI_EXIT_DISC even between routes from differen ASes */
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int igp_metric; /* Use IGP metrics when selecting best route */
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int prefer_older; /* Prefer older routes according to RFC 5004 */
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int deterministic_med; /* Use more complicated algo to have strict RFC 4271 MED comparison */
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u32 default_local_pref; /* Default value for LOCAL_PREF attribute */
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u32 default_med; /* Default value for MULTI_EXIT_DISC attribute */
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int capabilities; /* Enable capability handshake [RFC3392] */
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int enable_refresh; /* Enable local support for route refresh [RFC2918] */
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int enable_as4; /* Enable local support for 4B AS numbers [RFC4893] */
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int enable_extended_messages; /* Enable local support for extended messages [draft] */
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u32 rr_cluster_id; /* Route reflector cluster ID, if different from local ID */
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int rr_client; /* Whether neighbor is RR client of me */
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int rs_client; /* Whether neighbor is RS client of me */
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int advertise_ipv4; /* Whether we should add IPv4 capability advertisement to OPEN message */
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int passive; /* Do not initiate outgoing connection */
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int interpret_communities; /* Hardwired handling of well-known communities */
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int secondary; /* Accept also non-best routes (i.e. RA_ACCEPTED) */
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int add_path; /* Use ADD-PATH extension [draft] */
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int allow_local_as; /* Allow that number of local ASNs in incoming AS_PATHs */
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int gr_mode; /* Graceful restart mode (BGP_GR_*) */
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int setkey; /* Set MD5 password to system SA/SP database */
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unsigned gr_time; /* Graceful restart timeout */
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unsigned connect_delay_time; /* Minimum delay between connect attempts */
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unsigned connect_retry_time; /* Timeout for connect attempts */
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unsigned hold_time, initial_hold_time;
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unsigned keepalive_time;
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unsigned error_amnesia_time; /* Errors are forgotten after */
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unsigned error_delay_time_min; /* Time to wait after an error is detected */
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unsigned error_delay_time_max;
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unsigned disable_after_error; /* Disable the protocol when error is detected */
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char *password; /* Password used for MD5 authentication */
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struct rtable_config *igp_table; /* Table used for recursive next hop lookups */
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int check_link; /* Use iface link state for liveness detection */
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int bfd; /* Use BFD for liveness detection */
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};
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#define MLL_SELF 1
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#define MLL_DROP 2
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#define MLL_IGNORE 3
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#define GW_DIRECT 1
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#define GW_RECURSIVE 2
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#define ADD_PATH_RX 1
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#define ADD_PATH_TX 2
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#define ADD_PATH_FULL 3
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#define BGP_GR_ABLE 1
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#define BGP_GR_AWARE 2
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/* For peer_gr_flags */
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#define BGP_GRF_RESTART 0x80
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/* For peer_gr_aflags */
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#define BGP_GRF_FORWARDING 0x80
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struct bgp_conn {
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struct bgp_proto *bgp;
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struct birdsock *sk;
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uint state; /* State of connection state machine */
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struct timer *connect_retry_timer;
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struct timer *hold_timer;
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struct timer *keepalive_timer;
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struct event *tx_ev;
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int packets_to_send; /* Bitmap of packet types to be sent */
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int notify_code, notify_subcode, notify_size;
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byte *notify_data;
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u32 advertised_as; /* Temporary value for AS number received */
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int start_state; /* protocol start_state snapshot when connection established */
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u8 peer_refresh_support; /* Peer supports route refresh [RFC2918] */
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u8 peer_as4_support; /* Peer supports 4B AS numbers [RFC4893] */
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u8 peer_add_path; /* Peer supports ADD-PATH [draft] */
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u8 peer_enhanced_refresh_support; /* Peer supports enhanced refresh [RFC7313] */
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u8 peer_gr_aware;
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u8 peer_gr_able;
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u16 peer_gr_time;
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u8 peer_gr_flags;
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u8 peer_gr_aflags;
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u8 peer_ext_messages_support; /* Peer supports extended message length [draft] */
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unsigned hold_time, keepalive_time; /* Times calculated from my and neighbor's requirements */
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};
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struct bgp_proto {
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struct proto p;
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struct bgp_config *cf; /* Shortcut to BGP configuration */
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u32 local_as, remote_as;
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int start_state; /* Substates that partitions BS_START */
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u8 is_internal; /* Internal BGP connection (local_as == remote_as) */
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u8 as4_session; /* Session uses 4B AS numbers in AS_PATH (both sides support it) */
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u8 add_path_rx; /* Session expects receive of ADD-PATH extended NLRI */
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u8 add_path_tx; /* Session expects transmit of ADD-PATH extended NLRI */
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u8 ext_messages; /* Session allows to use extended messages (both sides support it) */
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u32 local_id; /* BGP identifier of this router */
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u32 remote_id; /* BGP identifier of the neighbor */
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u32 rr_cluster_id; /* Route reflector cluster ID */
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int rr_client; /* Whether neighbor is RR client of me */
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int rs_client; /* Whether neighbor is RS client of me */
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u8 gr_ready; /* Neighbor could do graceful restart */
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u8 gr_active; /* Neighbor is doing graceful restart */
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u8 feed_state; /* Feed state (TX) for EoR, RR packets, see BFS_* */
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u8 load_state; /* Load state (RX) for EoR, RR packets, see BFS_* */
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struct bgp_conn *conn; /* Connection we have established */
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struct bgp_conn outgoing_conn; /* Outgoing connection we're working with */
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struct bgp_conn incoming_conn; /* Incoming connection we have neither accepted nor rejected yet */
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struct object_lock *lock; /* Lock for neighbor connection */
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struct neighbor *neigh; /* Neighbor entry corresponding to remote ip, NULL if multihop */
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struct bfd_request *bfd_req; /* BFD request, if BFD is used */
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ip_addr source_addr; /* Local address used as an advertised next hop */
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rtable *igp_table; /* Table used for recursive next hop lookups */
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struct event *event; /* Event for respawning and shutting process */
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struct timer *startup_timer; /* Timer used to delay protocol startup due to previous errors (startup_delay) */
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struct timer *gr_timer; /* Timer waiting for reestablishment after graceful restart */
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struct bgp_bucket **bucket_hash; /* Hash table of attribute buckets */
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uint hash_size, hash_count, hash_limit;
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HASH(struct bgp_prefix) prefix_hash; /* Prefixes to be sent */
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slab *prefix_slab; /* Slab holding prefix nodes */
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list bucket_queue; /* Queue of buckets to send */
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struct bgp_bucket *withdraw_bucket; /* Withdrawn routes */
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unsigned startup_delay; /* Time to delay protocol startup by due to errors */
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bird_clock_t last_proto_error; /* Time of last error that leads to protocol stop */
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u8 last_error_class; /* Error class of last error */
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u32 last_error_code; /* Error code of last error. BGP protocol errors
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are encoded as (bgp_err_code << 16 | bgp_err_subcode) */
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#ifdef IPV6
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byte *mp_reach_start, *mp_unreach_start; /* Multiprotocol BGP attribute notes */
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unsigned mp_reach_len, mp_unreach_len;
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ip_addr local_link; /* Link-level version of source_addr */
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#endif
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};
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struct bgp_prefix {
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struct {
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ip_addr prefix;
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int pxlen;
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} n;
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u32 path_id;
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struct bgp_prefix *next;
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node bucket_node; /* Node in per-bucket list */
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};
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struct bgp_bucket {
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node send_node; /* Node in send queue */
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struct bgp_bucket *hash_next, *hash_prev; /* Node in bucket hash table */
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unsigned hash; /* Hash over extended attributes */
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list prefixes; /* Prefixes in this buckets */
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ea_list eattrs[0]; /* Per-bucket extended attributes */
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};
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#define BGP_PORT 179
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#define BGP_VERSION 4
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#define BGP_HEADER_LENGTH 19
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#define BGP_MAX_MESSAGE_LENGTH 4096
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#define BGP_MAX_EXT_MSG_LENGTH 65535
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#define BGP_RX_BUFFER_SIZE 4096
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#define BGP_TX_BUFFER_SIZE 4096
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#define BGP_RX_BUFFER_EXT_SIZE 65535
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#define BGP_TX_BUFFER_EXT_SIZE 65535
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static inline uint bgp_max_packet_length(struct bgp_proto *p)
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{ return p->ext_messages ? BGP_MAX_EXT_MSG_LENGTH : BGP_MAX_MESSAGE_LENGTH; }
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extern struct linpool *bgp_linpool;
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void bgp_start_timer(struct timer *t, int value);
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void bgp_check_config(struct bgp_config *c);
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void bgp_error(struct bgp_conn *c, unsigned code, unsigned subcode, byte *data, int len);
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void bgp_close_conn(struct bgp_conn *c);
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void bgp_update_startup_delay(struct bgp_proto *p);
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void bgp_conn_enter_openconfirm_state(struct bgp_conn *conn);
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void bgp_conn_enter_established_state(struct bgp_conn *conn);
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void bgp_conn_enter_close_state(struct bgp_conn *conn);
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void bgp_conn_enter_idle_state(struct bgp_conn *conn);
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void bgp_handle_graceful_restart(struct bgp_proto *p);
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void bgp_graceful_restart_done(struct bgp_proto *p);
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void bgp_refresh_begin(struct bgp_proto *p);
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void bgp_refresh_end(struct bgp_proto *p);
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void bgp_store_error(struct bgp_proto *p, struct bgp_conn *c, u8 class, u32 code);
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void bgp_stop(struct bgp_proto *p, unsigned subcode);
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struct rte_source *bgp_find_source(struct bgp_proto *p, u32 path_id);
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struct rte_source *bgp_get_source(struct bgp_proto *p, u32 path_id);
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#ifdef LOCAL_DEBUG
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#define BGP_FORCE_DEBUG 1
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#else
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#define BGP_FORCE_DEBUG 0
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#endif
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#define BGP_TRACE(flags, msg, args...) do { if ((p->p.debug & flags) || BGP_FORCE_DEBUG) \
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log(L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
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#define BGP_TRACE_RL(rl, flags, msg, args...) do { if ((p->p.debug & flags) || BGP_FORCE_DEBUG) \
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log_rl(rl, L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
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/* attrs.c */
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/* Hack: although BA_NEXT_HOP attribute has type EAF_TYPE_IP_ADDRESS, in IPv6
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* we store two addesses in it - a global address and a link local address.
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*/
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#ifdef IPV6
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#define NEXT_HOP_LENGTH (2*sizeof(ip_addr))
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static inline void set_next_hop(byte *b, ip_addr addr) { ((ip_addr *) b)[0] = addr; ((ip_addr *) b)[1] = IPA_NONE; }
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#else
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#define NEXT_HOP_LENGTH sizeof(ip_addr)
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static inline void set_next_hop(byte *b, ip_addr addr) { ((ip_addr *) b)[0] = addr; }
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#endif
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void bgp_attach_attr(struct ea_list **to, struct linpool *pool, unsigned attr, uintptr_t val);
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byte *bgp_attach_attr_wa(struct ea_list **to, struct linpool *pool, unsigned attr, unsigned len);
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struct rta *bgp_decode_attrs(struct bgp_conn *conn, byte *a, uint len, struct linpool *pool, int mandatory);
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int bgp_get_attr(struct eattr *e, byte *buf, int buflen);
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int bgp_rte_better(struct rte *, struct rte *);
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int bgp_rte_mergable(rte *pri, rte *sec);
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int bgp_rte_recalculate(rtable *table, net *net, rte *new, rte *old, rte *old_best);
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void bgp_rt_notify(struct proto *P, rtable *tbl UNUSED, net *n, rte *new, rte *old UNUSED, ea_list *attrs);
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int bgp_import_control(struct proto *, struct rte **, struct ea_list **, struct linpool *);
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void bgp_init_bucket_table(struct bgp_proto *);
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void bgp_free_bucket_table(struct bgp_proto *p);
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void bgp_free_bucket(struct bgp_proto *p, struct bgp_bucket *buck);
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void bgp_init_prefix_table(struct bgp_proto *p, u32 order);
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void bgp_free_prefix_table(struct bgp_proto *p);
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void bgp_free_prefix(struct bgp_proto *p, struct bgp_prefix *bp);
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uint bgp_encode_attrs(struct bgp_proto *p, byte *w, ea_list *attrs, int remains);
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void bgp_get_route_info(struct rte *, byte *buf, struct ea_list *attrs);
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inline static void bgp_attach_attr_ip(struct ea_list **to, struct linpool *pool, unsigned attr, ip_addr a)
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{ *(ip_addr *) bgp_attach_attr_wa(to, pool, attr, sizeof(ip_addr)) = a; }
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/* packets.c */
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void mrt_dump_bgp_state_change(struct bgp_conn *conn, unsigned old, unsigned new);
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void bgp_schedule_packet(struct bgp_conn *conn, int type);
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void bgp_kick_tx(void *vconn);
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void bgp_tx(struct birdsock *sk);
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int bgp_rx(struct birdsock *sk, uint size);
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const char * bgp_error_dsc(unsigned code, unsigned subcode);
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void bgp_log_error(struct bgp_proto *p, u8 class, char *msg, unsigned code, unsigned subcode, byte *data, unsigned len);
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/* Packet types */
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#define PKT_OPEN 0x01
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#define PKT_UPDATE 0x02
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#define PKT_NOTIFICATION 0x03
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#define PKT_KEEPALIVE 0x04
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#define PKT_ROUTE_REFRESH 0x05 /* [RFC2918] */
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#define PKT_BEGIN_REFRESH 0x1e /* Dummy type for BoRR packet [RFC7313] */
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#define PKT_SCHEDULE_CLOSE 0x1f /* Used internally to schedule socket close */
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/* Attributes */
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#define BAF_OPTIONAL 0x80
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#define BAF_TRANSITIVE 0x40
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#define BAF_PARTIAL 0x20
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#define BAF_EXT_LEN 0x10
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#define BA_ORIGIN 0x01 /* [RFC1771] */ /* WM */
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#define BA_AS_PATH 0x02 /* WM */
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#define BA_NEXT_HOP 0x03 /* WM */
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#define BA_MULTI_EXIT_DISC 0x04 /* ON */
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#define BA_LOCAL_PREF 0x05 /* WD */
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#define BA_ATOMIC_AGGR 0x06 /* WD */
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#define BA_AGGREGATOR 0x07 /* OT */
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#define BA_COMMUNITY 0x08 /* [RFC1997] */ /* OT */
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#define BA_ORIGINATOR_ID 0x09 /* [RFC1966] */ /* ON */
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#define BA_CLUSTER_LIST 0x0a /* ON */
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/* We don't support these: */
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#define BA_DPA 0x0b /* ??? */
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#define BA_ADVERTISER 0x0c /* [RFC1863] */
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#define BA_RCID_PATH 0x0d
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#define BA_MP_REACH_NLRI 0x0e /* [RFC2283] */
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#define BA_MP_UNREACH_NLRI 0x0f
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#define BA_EXT_COMMUNITY 0x10 /* [RFC4360] */
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#define BA_AS4_PATH 0x11 /* [RFC4893] */
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#define BA_AS4_AGGREGATOR 0x12
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#define BA_LARGE_COMMUNITY 0x20 /* [draft-ietf-idr-large-community] */
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/* BGP connection states */
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#define BS_IDLE 0
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#define BS_CONNECT 1 /* Attempting to connect */
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#define BS_ACTIVE 2 /* Waiting for connection retry & listening */
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#define BS_OPENSENT 3
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#define BS_OPENCONFIRM 4
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#define BS_ESTABLISHED 5
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#define BS_CLOSE 6 /* Used during transition to BS_IDLE */
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#define BS_MAX 7
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/* BGP start states
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*
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* Used in PS_START for fine-grained specification of starting state.
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*
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* When BGP protocol is started by core, it goes to BSS_PREPARE. When BGP
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* protocol done what is neccessary to start itself (like acquiring the lock),
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* it goes to BSS_CONNECT. When some connection attempt failed because of
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* option or capability error, it goes to BSS_CONNECT_NOCAP.
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*/
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#define BSS_PREPARE 0 /* Used before ordinary BGP started, i. e. waiting for lock */
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#define BSS_DELAY 1 /* Startup delay due to previous errors */
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#define BSS_CONNECT 2 /* Ordinary BGP connecting */
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#define BSS_CONNECT_NOCAP 3 /* Legacy BGP connecting (without capabilities) */
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/* BGP feed states (TX)
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*
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* RFC 4724 specifies that an initial feed should end with End-of-RIB mark.
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*
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* RFC 7313 specifies that a route refresh should be demarcated by BoRR and EoRR packets.
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*
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* These states (stored in p->feed_state) are used to keep track of these
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* requirements. When such feed is started, BFS_LOADING / BFS_REFRESHING is
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* set. When it ended, BFS_LOADED / BFS_REFRESHED is set to schedule End-of-RIB
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* or EoRR packet. When the packet is sent, the state returned to BFS_NONE.
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*
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* Note that when a non-demarcated feed (e.g. plain RFC 4271 initial load
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* without End-of-RIB or plain RFC 2918 route refresh without BoRR/EoRR
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* demarcation) is active, BFS_NONE is set.
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*
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* BFS_NONE, BFS_LOADING and BFS_REFRESHING are also used as load states (RX)
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* with correspondent semantics (-, expecting End-of-RIB, expecting EoRR).
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*/
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#define BFS_NONE 0 /* No feed or original non-demarcated feed */
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#define BFS_LOADING 1 /* Initial feed active, End-of-RIB planned */
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#define BFS_LOADED 2 /* Loading done, End-of-RIB marker scheduled */
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#define BFS_REFRESHING 3 /* Route refresh (introduced by BoRR) active */
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#define BFS_REFRESHED 4 /* Refresh done, EoRR packet scheduled */
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/* Error classes */
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#define BE_NONE 0
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#define BE_MISC 1 /* Miscellaneous error */
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#define BE_SOCKET 2 /* Socket error */
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#define BE_BGP_RX 3 /* BGP protocol error notification received */
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#define BE_BGP_TX 4 /* BGP protocol error notification sent */
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#define BE_AUTO_DOWN 5 /* Automatic shutdown */
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#define BE_MAN_DOWN 6 /* Manual shutdown */
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/* Misc error codes */
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#define BEM_NEIGHBOR_LOST 1
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#define BEM_INVALID_NEXT_HOP 2
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#define BEM_INVALID_MD5 3 /* MD5 authentication kernel request failed (possibly not supported) */
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#define BEM_NO_SOCKET 4
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#define BEM_LINK_DOWN 5
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#define BEM_BFD_DOWN 6
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#define BEM_GRACEFUL_RESTART 7
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/* Automatic shutdown error codes */
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#define BEA_ROUTE_LIMIT_EXCEEDED 1
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/* Well-known communities */
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#define BGP_COMM_NO_EXPORT 0xffffff01 /* Don't export outside local AS / confed. */
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#define BGP_COMM_NO_ADVERTISE 0xffffff02 /* Don't export at all */
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#define BGP_COMM_NO_EXPORT_SUBCONFED 0xffffff03 /* NO_EXPORT even in local confederation */
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/* Origins */
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#define ORIGIN_IGP 0
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#define ORIGIN_EGP 1
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#define ORIGIN_INCOMPLETE 2
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/* Address families */
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#define BGP_AF_IPV4 1
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#define BGP_AF_IPV6 2
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#ifdef IPV6
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#define BGP_AF BGP_AF_IPV6
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#else
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#define BGP_AF BGP_AF_IPV4
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#endif
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#endif
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